Dibenzothienobisbenzothiophene-a novel fused-ring oligomer with high field-effect mobility

Thienoacene‐Based Organic Semiconductors

“…[ 12 , 44 ] In contrast, π -extended compound 13 was reported to show improved mobilities of up to 0.15 cm 2 V − 1 s − 1 . [ 42 ] As mentioned above, the method for the synthesis of 13 is less selective and affords regioisomeric mixtures (Scheme 3 ). In fact, the contamination with regioisomers required an elaborate experimental process to obtain high-performance 13 -based organic thin-fi lm transistors (OTFTs); high performance was achieved by depositing 13 on a substrate after a substantial fraction of the freshly loaded 13 in the evaporation source had already sublimed.…”

“…(DBTBT, 13 ), [ 42 ] which showed very promising performance with μ FET of 0.15 cm 2 V − 1 s − 1 and I on / I off > 10 6…”

“…In fact, the contamination with regioisomers required an elaborate experimental process to obtain high-performance 13 -based organic thin-fi lm transistors (OTFTs); high performance was achieved by depositing 13 on a substrate after a substantial fraction of the freshly loaded 13 in the evaporation source had already sublimed. [ 42 ] This means that the highly volatile regioisomers fi rst evaporate and isomeric pure 13 is then deposited on the substrate. Without such operations, the resulting OFETs showed poor device characteristics, including lowered mobilities (0.03 cm 2 V − 1 s − 1 ).…”

“…[ 12 ] Readily available reaction was developed by Müllen and co-workers, which involved the intramolecular coupling reaction of aromatic methyl sulfoxides with an activated aromatic building block in the presence of strong acids (Scheme 2 b). [ 42 ] Armed with this key reaction and its applicability to various intermediates possessing methyl sulfoxide functionalities at appropriate positions, they successfully developed a series of DBT-based materials (i.e., 2 , 13, and 14 , Scheme 3 ). In the synthesis of 13 , treatment of the precursor (3,7-bis[2-(methylsulfi nyl)phenyl]DBT) with trifl uoromethanesulfonic acid also gave two possible regioisomers depicted in the brackets, the separation of which was reported to be diffi cult in practice due to the rather small differences in sublimation temperature.…”

High Carrier Mobility of Organic Field‐Effect Transistors with a Thiophene–Naphthalene Mesomorphic Semiconductor

“…Recently, studies have been extended to the application of these mesomorphic materials to organic electronic devices such as organic thin-film transistors (OTFTs), organic light-emitting diodes (OLEDs), and so on. Some of the characteristic properties of LC semiconductors, [1,2] such as their self-assembling nature, ambipolar charge transport, electrically inactive domain boundaries, and good solubility in ordinary organic solvents, make them attractive candidates for application in these devices.Crystalline organic semiconductors such as pentacene [3][4][5] and oligothiophenes [6][7][8] have been extensively studied for use in OTFTs because of their relatively high field-effect mobilities. However, pentacene is easily photo-oxidized in air because of its relatively high-lying highest occupied molecular orbital (HOMO) energy level and its narrow band gap.…”